Porsche has been steadily bolstering its Panamera line since the car was first introduced adding models like the V6, Hybrid and GTS, and starting next year, it is adding a new model to the mix, the Panamera Platinum Edition. The 2013 Porsche Panamera Platinum Edition goes on sale on January 5, and it is only offered on the V6 models with a starting price of $80,500 for rear-wheel-drive and $84,600 for the all-wheel-drive Panamera 4 version; neither of these prices includes the $975 destination c